OPEC’s first deal to cut output in eight years has spurred a running of the oil bulls.

Prices surged, breaching $50 a barrel, since the Organization of Petroleum Exporting Countries agreed to the cut on Sept. 28 in Algiers. The group, which pumped at a record in September, will decide on quotas for its members at an official meeting in Vienna on Nov. 30. Futures also got a boost from a five-week stretch of falling U.S. crude stockpiles.

“The market went haywire in the week and a half after the OPEC agreement,” said Stephen Schork, president of the Schork Group Inc., a consulting company in Villanova, Pennsylvania. “The bulls were ready and really jumped in. Since OPEC, there’s been a tick, tick, tick higher.”

Money managers increased long positions in West Texas Intermediate crude futures and options to the highest level in more than two years during the week ended Oct. 4, according to the Commodity Futures Trading Commission. Bets on falling prices dropped for a second week. Brent longs also rose, leaving the combined length of the two benchmark contracts at a record.

WTI futures increased 9 percent to $48.69 a barrel in the report week and extended that rally to close Thursday above $50 for the first time since June. Prices rose 3.1 percent to $51.35 a barrel Monday, the highest close since July 2015.

Unanswered Questions

“This is the post-OPEC wave,” said John Kilduff, a partner at Again Capital LLC, a New York-based hedge fund that focuses on energy. “This market has rewarded the OPEC rhetoric. Let’s see if their deeds match their words.”

The OPEC deal, which would trim output to a range of 32.5 million to 33 million barrels a day, is due to be finalized at the Vienna summit next month. While OPEC will decide on quotas for individual members, there may also be exemptions for nations including Iran, which is increasing production after the lifting of international sanctions in January.

“They left certain unanswered questions,” said Tim Evans, an energy analyst at Citi Futures Perspective in New York. “We’ll have to see if they formulate targets at the Nov. 30 meeting in Vienna and then have to wait to see what’s the ultimate rate of compliance. This is a story that will continue well into the first quarter of next year.”

U.S. crude stockpiles dropped by 2.98 million barrels to 499.7 million in the week ended Sept. 30, the lowest since January, Energy Information Administration data show. Inventories reached 543.4 million barrels in the week ended April 29, the highest since 1929.

Money managers’ long position in WTI, or bets on rising prices, climbed to 353,162 futures and options. Shorts fell 30 percent. The resulting net-long position increased 40 percent to the highest level since May 2015.

In the Brent market, money managers boosted bullish bets by 11 percent to 422,500 during the week, according to data from ICE Futures Europe. Speculative bets that prices will rise outnumbered short positions by 358,699 lots, the London-based exchange said in its weekly report.

In other markets, net-bullish bets on gasoline rose 33 percent to 30,737 contracts, the highest since March, as futures increased 7.6 percent in the report week. Wagers on ultra low sulfur diesel went from net short to net long. Futures climbed 10 percent.

The fundamentals don’t support prices at this level, according to Schork. OPEC has yet to agree on specific cuts and U.S. crude stockpiles remain at the highest seasonal level in more than 20 years.

“There’s been a lot of hype about the agreement although we won’t see any cut until next year,” Schork said. “Momentum is in the bulls’ favor. There comes a point when you have to stop beating your head against the wall and my head is sore.”